[2+2]-Photocycloaddition of N-Benzylmaleimide to Alkenes As an Approach to Functional 3-Azabicyclo[3.2.0]heptanes.

A one-step synthesis of functionalized 3-azabicyclo[3.2.0]heptanes by [2+2]-photochemical intermolecular cycloaddition of N-benzylmaleimide to alkenes was elaborated. The obtained compounds were easily transformed into the bi- and tricyclic analogues of piperidine, morpholine, piperazine, and GABA, which are advanced building blocks for drug discovery.